Such heat could prove dangerous for the players, with their predicament compounded by the altitude in Denver – dubbed the 'mile-high city' - with the stadium 5,280 feet above sea level.

Van Gaal has experience of playing in such conditions, with his Holland side forced to play in similar heat in Fortaleza at the World Cup in Brazil, which forced FIFA to introduce drinks breaks during the game.

“It's unbelievable that we play at two o’clock,” said van Gaal.

“We will adapt to te situation because all the players will play for 45 minutes, except Tom Cleverley and Tyler Blackett.

“For the players, it is very hard and I hope I can persuade the referee to have a drinks break as I did in Fortaleza.

“We have a sports science department and it shall be done very well with the conditions, especially those players who will play 45 minutes.”

Check out the best photos from United's first pre-season run-out against LA Galaxy: